Once a haven for wildlife, Poplar Island, in the mid-Chesapeake Bay region, was slipping away at a rate of more than 13 feet a year because of the rapid erosion brought on by sea-level rise and land subsidence. The island was well on the way to becoming just another sand shoal.
Maps and records from the 1600s describe Poplar Island as more than 2,000 acres. By 1990, the island had been reduced to remnants totaling less than 10 acres.
The Paul S. Sarbanes Ecological Restoration at Poplar Island began with the goal of restoration within the historic island footprint.
Using dredged material from Chesapeake Bay shipping channels, workers are steadily rebuilding the island and restoring its habitat. Poplar Island is now 1,140 acres and will be expanded by an additional 550 acres. The project has also restored Poplar Harbor, a 300-acre protected embayment on the leeward side of the island. It is hoped that by restoring that area of calm, shallow water, local beds of submerged aquatic vegetation, or SAV, will recolonize to historic levels.
Restored salt marshes on Poplar Island fall into two distinct areas, low marsh and high marsh, divided by the elevation and associated plants. The low marsh zone is dominated by saltmarsh cordgrass (Spartina alterniflora). The high marsh zone consists of saltmeadow hay (Spartina patens), saltgrass (Distichlis spicata), and high-tide bush (Iva frutescens).
During monitoring, U.S. Fish and Wildlife Service biologists were pleased to discover saltmarsh periwinkles (Littorina irrorata) using the newly restored wetlands on Poplar Island. Periwinkles are snails commonly found in the intertidal zone of brackish and salt water marshes. Because they are air breathers, periwinkles are often found during periods of high water above the waterline on stems of saltmarsh cordgrass.
They are a crucial component of the ecosystem, feeding on detritus (decaying matter) and algae, and are an important source of food for waterbirds, crabs and fish. This was an exciting find as saltmarsh periwinkles are an integral part of a healthy salt marsh, indicating that the wetlands restoration efforts at Poplar Island are successfully re-establishing the lost island habitat.
SAV is considered an indicator of the health of the Chesapeake Bay. SAV monitoring in the shallow waters around the island has been ongoing since 2002 and occurs in May, July and September each year.
Two dominant species have been found in Poplar Harbor: horned pondweed (Zannichellia palustris) and widgeon grass (Ruppia maritima). Poplar Harbor has continued to display increases in SAV coverage and density.
Biologists have also been using Christmas trees to provide shelter and nesting areas. Each year, roughly 250 trees are hauled on boats to Poplar Island and strategically placed on habitat islands located in created wetlands. These are meant to provide both cover and nesting sites for colonial waterbirds such as the snowy egret (Egretta thula) and cattle egret (Bubulcus ibis).
Christmas tree debris piles are also placed in the newly created wetlands in an effort to attract other bird, mammal and amphibian species. Small rodents such as meadow voles (Microtus pennsylvanicus) and white-footed mice (Peromyscus leucopus) have also been observed within the debris piles. There are several smaller islands close by where mammals (like deer muskrat) can swim back and forth. Many of the smaller mammals (voles, mice) were still on the remnant of the island and have done well with the added habitat. Some small mammals may also have moved onto Poplar when machinery was transported.
Stumps and discarded Christmas trees placed in the marshes and upland areas also provide cover and nesting habitat for waterfowl such as American black duck (Anas rubripes).
The American black duck, one of North America's wariest waterfowl, is a target species for the project. Small islands and isolated marshes are the last stronghold for American black ducks nesting in the Bay. Only a few, small, nesting islands remain.
Commonly observed birds include: osprey (Pandion haliaetus), bald eagles (Haliaeetus leucocephalus), double-crested cormorants (Phalacrocorax auritus), as well as colonial waterbirds, shorebirds and waterfowl. Since the restoration began, more than 170 bird species have been recorded at Poplar Island, 25 of which have been nesting. In 1996, 10 species of birds were observed at on the Island, two or three of which were documented as nesting; further evidence of the successful ongoing restoration efforts at the present site.
At completion, Poplar Island will be half upland habitat and half wetlands. Trees, shrubs and grasses in uplands will support terrapins, birds and mammals, including squirrels and deer.
The wetlands, a combination of low marshes and high marshes, will provide habitat for a wide range of animals including, fish, shrimp, crabs, shorebirds, wading birds and mammals. Poplar Island, once on the verge of disappearing, is now an international model for the beneficial use of dredged material and wildlife habitat restoration.
For information about the Paul S. Sarbanes Ecological Restoration at Poplar Island, visit www.nab.usace.army.mil/Projects/PoplarIsland/Intro.htm.